Ureaplasma urealyticum is distinguished from other human mycoplasmas by which laboratory characteristic?

• A Ability to grow on media lacking serum or cholesterol
• B Hydrolysis of urea, producing ammonia and raising the pH of the medium ✓
• C Formation of large colonies visible to the naked eye within 24 hours
• D Positive oxidase reaction on Christensen's urea agar

Explanation

Ureaplasma species possess a potent urease enzyme and are named for their ability to split urea into ammonia, which alkalinises the medium; this is the basis of their identification. Like all mycoplasmas they require sterol-rich media and produce tiny colonies, so options A and C are wrong. They are oxidase negative, ruling out option D. Clinically this urease activity links Ureaplasma to urethritis and to ammonium magnesium phosphate stone formation.

Reference: Ananthanarayan and Paniker's Textbook of Microbiology, 12th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

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